HTML5validator exits with return code 24 when invalid root given

[Cyb3r-Jak3]

I seem to have found an edge case where if the --root option is set to a folder that doesn't exist then the default help text is displayed for vnujar.

Example:

> html5validator --root INVALID --log DEBUG

INFO:html5validator.cli:Files to validate:

INFO:html5validator.cli:Number of files: 0
DEBUG:html5validator.validator:['java', '-jar', '/home/j/.local/lib/python3.6/site-packages/vnujar/vnu.jar', '--errors-only', '--stdout', '--asciiquotes']
DEBUG:html5validator.validator:['Error: No documents specified.', 'Usage:', '    vnu-runtime-image/bin/vnu OPTIONS FILES (Linux or macOS)', '    vnu-runtime-image\\bin\\vnu.bat OPTIONS FILES (Windows)', '    java -jar ~/vnu.jar OPTIONS FILES (any system with Java8+ installed)', '...where FILES are the documents to check, and OPTIONS are zero or more of:', '    --errors-only --Werror --exit-zero-always --stdout --asciiquotes', '    --user-agent\xa0USER_AGENT --no-langdetect --no-stream --filterfile\xa0FILENAME', '    --filterpattern\xa0PATTERN --css --skip-non-css --also-check-css --svg', '    --skip-non-svg --also-check-svg --html --skip-non-html', '    --format\xa0gnu|xml|json|text --help --verbose --version', 'For detailed usage information, try the "--help" option or see:', '  http://validator.github.io/', 'To read from stdin, use "-" as the filename, like this: "java -jar vnu.jar - ".', 'To run the checker as a standalone Web-based service, open a new terminal', 'window and invoke the checker like this', '    java -cp vnu.jar nu.validator.servlet.Main 8888', '    vnu-runtime-image/bin/java nu.validator.servlet.Main 8888', '    vnu-runtime-image\\bin\\java -cp vnu.jar nu.validator.servlet.Main 8888', '...then open http://127.0.0.1:8888 in a browser.', 'After that, to check documents locally using the packaged HTTP client, do this:', '    java -cp vnu.jar nu.validator.client.HttpClient FILES', '    vnu-runtime-image/bin/java nu.validator.client.HttpClient FILES', '    vnu-runtime-image\\bin\\java nu.validator.client.HttpClient FILES']
Error: No documents specified.
Usage:
    vnu-runtime-image/bin/vnu OPTIONS FILES (Linux or macOS)
    vnu-runtime-image\bin\vnu.bat OPTIONS FILES (Windows)
    java -jar ~/vnu.jar OPTIONS FILES (any system with Java8+ installed)
...where FILES are the documents to check, and OPTIONS are zero or more of:
    --errors-only --Werror --exit-zero-always --stdout --asciiquotes
    --user-agent USER_AGENT --no-langdetect --no-stream --filterfile FILENAME
    --filterpattern PATTERN --css --skip-non-css --also-check-css --svg
    --skip-non-svg --also-check-svg --html --skip-non-html
    --format gnu|xml|json|text --help --verbose --version
For detailed usage information, try the "--help" option or see:
  http://validator.github.io/
To read from stdin, use "-" as the filename, like this: "java -jar vnu.jar - ".
To run the checker as a standalone Web-based service, open a new terminal
window and invoke the checker like this
    java -cp vnu.jar nu.validator.servlet.Main 8888
    vnu-runtime-image/bin/java nu.validator.servlet.Main 8888
    vnu-runtime-image\bin\java -cp vnu.jar nu.validator.servlet.Main 8888
...then open http://127.0.0.1:8888 in a browser.
After that, to check documents locally using the packaged HTTP client, do this:
    java -cp vnu.jar nu.validator.client.HttpClient FILES
    vnu-runtime-image/bin/java nu.validator.client.HttpClient FILES
    vnu-runtime-image\bin\java nu.validator.client.HttpClient FILES

> echo $?
24

I'm not sure the best way to solve this and if we even should (See edit).

My best way would be to check if root exists?

Edit: I do believe that this should be fixed as it is being detected that there are no files to validate but it still continues to run.